How might the government deal with a huge company that has no competitors and is charging customers high prices?

A Break the company up into smaller competing firms
B Fine the company based on its profits for a given year
C Forced the company to pay taxes at a higher rate
D Assign a government agent to observe the companies leadership

A Break the company up into smaller competing firms

Breaking up the company into smaller competing firms would increase competition in the market, leading to lower prices for consumers. This would prevent the company from abusing its dominant position and charging high prices.